Welt seam



Nov. '27', 1951 E, A WIRT 2,576,324

' WELT sEAM Fuad sepi. 11, 1948 2 sHEETsf-SHEET 1 Patented Nov. 27, 1951 wrn 'sEAM Erwin A. Wirt, Clifton, N. J., assignorto -The Howard Zink Corporation, Fremont, Ohio, a

corporation of Ohio.

application September 11, 1948., serial No. 48,849

1 invention Vrelates to an improved Welt seam between flexible sheet materials such as pieces of fabric, and to a novel method of forming such seam.

TheV invention has among its objects the provision of a novel Welt seam joining pieces of flexible sheet material,, such seam being characterifzedj by its thinness,v compactness, and strength.

More particularly, another object of the inventionresid-es in the provision of a Welt seam of'such characterV that the welt may be made without cord or lling.

'IA-'hes/ev and' further objects of the Invention will be more readily apparentin the following descriptien of a, preferred embodiment of the. seam and a. preferred. embosiimcnt of, the. method of the; inventioa,

Heretofore. in the formatimlA of seams., between pieces.. of fleXib1f-:-V Sheet Inaterial,b as. inI the, making, of automobile. seat, covers, covers for furniture such aschairs, and also inb the formation of pieces of lugggsge,l a filled, or cord, containing, Welt has, been'employed at .the seam to reinforceit. The;k Welt, there.. emrloyed was; provided with. a filling. such, as; a cord so that the Outer; edge of the=- lt sliced; an 'amreciame distanceabove;l thev Scam- Such Seamwas: undu1y-prominent-due.to

opsi-landing Welt, and also Was not particulai-lylonedastine because; of-thefact thatthe upsvta, r1' i ix -1gl welt wasisubjectedl to repeated: flexure;

wasV true particularlyonf automobi-le seat coyersand the like, where the welt wassu-bjected to repeated; fiexurei as one's. body brushed against itL in, enteringl ami'leavingr theautomobile andialso by reason; Qf= the. contact therewith. of; occupants of: the automobilel during riding thereim Imforming such. prior Welt seam a pluralityof operations were. employedl. Typical of the methodsvoffmakingflsuchseam wasthat in which themelt.wasaforme1:i-,l in-a` separate operation; ,with a, cord-` orf filling aroundwhich ay covering` Was sewed. Such welt was then sewed aton e sidefito one. of: theV piecesof: fiexible sheet material` t obe joined;l where-upontheother piece ofA such materialawas superimposed'fluponthe-welt, a binding was putover, the. edgesof2 the fiex-iblesheet material; and:thebindingwas4 then sewedin place; Suohs operation was-time-consuming and'V costly; due-K to the pluralityof manipulations required:

The-we1t seamofthe present-invention em ployflsI` a thin cordless Weltl formed,i for exampleI from4a-foldedstape= The-welt-is-so locatedin the seam thati a relatively small-portion thereofV a t thelfomrexpesed--and-so that the fom'm the f 2 Claims. (Cl. 1112:-262

Welt lies snugly against one or the other of the pieces of thin fiexible material. The method of the invention comprises the simultaneous form.- ing of the welt and binding, the simultaneous' assemblingof the pieces of material to be joined to the Welt and binding, and the concurrent s'titchingof the parts together, whereby the seam is formed in one continuous operation.

The invention will be more readily understood by reference to the accompanying drawings., which form a part of the specification, in Which Figure 1 is a view in perspective of a portion ofan automobile seat provided with a seat cover having a seam made in accordance vwith the invention;

Figure 2 is a view in vertical cross-section through such seam', the section beingtaken along the line 2--2 in Figure 1;

Figure 3 is a view in perspective of a portionof a' sewing machine bymea-ns of which the method of making the seam may be practi'ced, the portion4 of -themachine at` the sewing neediesand thel table carrying the forming mechanisms for the welt and binding being shown;

FigureA 4 is aview in plan of'x the binding member forming and guiding' mechanism;

Figure 5, is a view; in end` elevation of the` bind'- ing member forming mechanism, theA view' bein taken along the line 5-5 in Figure 4:;

Figure 6 is aview in plan of the Welt. member forming and guiding mechanism;

Figure 7 is a view in e'nd elevation of the mechallism shown in Figure 6,v the view being` taken from line 'I-'I'LFigurejGi and Figurev 8 is 'a view in vertical cross-section through the seam, as it 'issues from the sewing maohine, the sectionbeing taken along, the line S-J-B'in both Figures 3 and 4.

Although, a's above indicated, thewelt seam of the present invention, may be employed' to. advantageina variety, of articleslsuch. as furniture, luggage, and thelike, for the purposes of illustration,,it is here shown incorporated in an automobile seat cover. In Figure 1 suchcover, shown generally at. 2,,is disposed on an automobile seat 4. The cover, in thisV instance,,isfOrmedwitlia seat panel 6, al front panel 8, and a sidepanel HL, thewelt seam made in accordance with. theinventionzbetween parts 6 and 8 being designated IZ', and'that between parts 6 and IO being designated l4, the seams being disposed slightly below the rounded forward and side edgesof theV seat.

A,considerationl of Figure 2,wi1l.show thestructure'ofthe seam of the invention... Frontpanell. is provided at its upper edge with a fold lil, the

inner portion of such edge below the fold being designated at IG. The portion of the seat panel 6 beneath the bend in its forward edge over the forward edge of the seat is designated l4. Edge portions |4 and IB lie generally parallel to each other, as shown, although it is, of course, to be understood that actually the portion of the seam below the Welt 20 will be pulled more closely together than is shown in Figure 2.

The Welt 20 is composed of a tape folded longitudinally of itself at 22 so as to have a U crosssection, flap 24 of the Welt member lying in con-V tact with the inner surface of edge portion l4 of panel 6, and flap 26 lying in contact with the inner surface of edge portion l6 of panel 8. Binding member 28, formed of a tape folded longitudinally of itself, has a bight portion 30, the inner surface of which closelyadjoins the bottom edges of portions [4 and |6 of the panels. The inner surface of flap 32 of the binding member contacts the outer surface of edge portion l4 of panel 6. Flap 34 ofV the binding member lies between the main portion of panel 8 and its inwardly folded edge 'l6 so as to lie intimately in contact therewith.

. In the seam shown, the folded edge 22 of the welt member lies substantially on the same level with the top of fold |8 of panel 8, so that when the seam is viewed from the exterior a relatively thinV line of Welt is seen. The components of the seam are secured together, in this instance, by two parallel lines of stitching, 38 and 38, which extend longitudinally of the seam. stitching 36 extends, as shown through part 14, the flaps 24 and 26 of Welt member 20 relatively close to the fold 22 in the latter, and the upper portion of edge IB of panel 8, in that order. stitching 38 extends as shown through flap member 32, edge |4 of panel 6, edge |6 of panel 8, and flap member 34, in that order.

The pieces of flexible sheet material, 6 anda, of the automobile seat cover may be made of cloth, fiber, leather, and the like. The Welt member 20, although in this embodiment preferably being -made of plastic material such as polyvinyl chloride, or cellulose acetate, may also be made of cloth impregnated with a plastic material such as the above or paper. The same materials are also suitable for making the binding member 28, although ordinarily it is preferred to employ a cloth tapefor this purpose.

Although two rows of stitching are shown and described for fastening the elements composing the seam together, it is to be understood that any desired Vnumber of rows of stitching in excess of two may also be used. In the preferred embodiment the first row of stitching passes through only the edges of the pieces of flexible material joined together and the Welt member, and the second line'v of stitching passes through only one flap of the binding member, the edge of one piece of flexible material, the infolded edge of the other piece of flexible material, and the second flap of the binding member, in that order. It is to be understood, however, that within the scope of the invention one or both of the side flaps of the binding member may be extended sufficiently so that the first line of stitching extends through them, and that the Welt member may, if desired, be made sufficiently wide so that the second line of stitching passes through the edges of the aps of the welt member as well as through the other members shown in Figure 2 and above described.

The apparatus shown in Figures 3 to 7, incluslve, may be used to advantage in the formation of the seam shown in Figure 2 in accordance With the method of the invention. In Figure 3 there is shown a portion of the sewing machine bed in the vicinity of the needle carrying head 42, whichisreciprocated vertically by conventional drive means, not shown. Head 42 has associated therewith a conventional presser foot 44, Which is selectively retractable, also by means not shown. The bed carries on its forward end the sewing machine table 48 upon which are mounted the mechanisms presently to be described for forming and guiding the components of the seam. Side extensions in the form of extension pieces 50 and 52 are provided on either side of the bed 40.

The tape from which the welt member 20 is formed is designated 20' in Figures 3, 6, and 7. Tape 20', fed from a source, not shown, associated with the sewing machine, is led to the Welt forming and guiding mechanism 54 from which it is- Sues as the folded welt with the closed edge or bight 22 thereof at the left in Figures 3 to '7, inclusive. The material forming the seat cover panel 6 is fed into the sewing machine With its righthand edge to be joined by the seam parallel to the line of issuance of Welt 20 from means 54 and beneath such Welt, as shown in Figure 3. The piece of material to form front panel portion 8 is fed into the sewing machine with its main body portion superimposed upon the main body portion of panel 8, but with its right-hand edge to be joined at the seam flexed upwardly away from panel 6 by the left-hand edge of Welt-forming mechanism 54. Such condition persists until piece 8 has cleared such welt forming mechanism, whereupon its edge to be joined falls so that it closely confronts and lies generally parallel to the corresponding edge of panel 6, the Welt member`20 lying between such edges in the position it is tol occupy in the finished seam. At the point past guiding mechanism 54 at which the two edges of pieces 8'and 8 substantially contact each other, they are guided laterally and vertically by mechanism 56 which also applies to such edges, in embracing relationship therewith, the binding member 28, as shown in Figure 4. Immediately to the rear of mechanism 56, which also performs the function of forming the tape shown at 28' fed from a source, not shown, into the U-shaped binding member 28, the assembled components of the seam, traveling in the direction indicated by the arrow in Figure 4, are 'engaged by the needles 86 and 88 carried by head 42. AIt is to be understood that conventional shuttle mechanism is provided beneath the table Whereby each needle and its shuttle form a separate line of stitching.

The structure of the seam l2' as .it issues from the sewing machine is shown in Figure 8. In such figure the parts corresponding to those shown in Figure 2 are designated by the same reference characters. The seam as formed, as shown in Figure 8, assumes the appearanceV shown in Figure 2 when the panel 8 is folded clockwise in Figure 8 aboutthe edge of flap 34 of the binding member.

The structure of the welt forming .and guiding mechanism 54 will be more readily understood by reference to Figures 6 and '7. Tape 20' is led into the mouth 64 of such mechanism over the guiding plate 66 which allows it to be turned at right angles. The tape then passes into the vertically vcurved passageway 10 (see Figure 7) in body 68, such passageway in its first portion becoming increasingly Wider inplan, as shown in Figure 6, while becoming increasingly narrower in side'elevation,.as shown in Figure 3. As a result of theV vertical curvaturerof passageway 1.0

and its progressive widening in the direction of travel of the tape, the latter is progressively formed into an increasingly more clearly defined U shape. The latter part of the passageway through body 68, designated ll, is of uniform Width in plan but progressively decreasing in height. In passageway 'H there is positioned a longitudinally disposed centrally located folding blade 12 about which the tape is longitudinally folded, as shown in Figure 6. Mechanism 54 is mounted so that the path of travel of the Welt issuing therefrom may be adjusted laterally with respect to the paths of travel of the other components of the seam through the sewing machine. Such attaching means takes the form of the strap 58, through slots 59 in which the attaching screws 58, threaded into the intermediate supporting plate S2 afiixed to table 48, extend.

In Figures 4 and 5 the structure of the binding member forming and. guiding mechanism 56 is shown in detail. Such mechanism has a main body portion 14 extending at right angles to the direction of travel of the components of the seam through the sewing machine. lSuch body is likewise adjustably mounted on the seWing machine; this is accomplished through the medium of supporting strap 16 through a slot 19 in which the mounting screws 11, threaded into the sewing machine table, extend. Tape 28, which is to form the binding member, enters the mouth 18 of mechanism 56 and travels through a channel 8| which progressively narrows in end elevation, but Which progressively increases in width, as shown in Figures 5 and 4, respectively. Body 14 is provided with a longitudinally extending aperture 15 through the side wall of channel 8I to facilitate threading of the tape through the passage.

The described configuration of channel 8l causes tape 28' to assume a U-shape With its bight upwardly in Figure 4 and rearwardly in Figure 5 as the tape travels toward the left-hand end of the channel as shown in these figures. At the left-hand end of body 14 there is positioned a block 84 having an open sided channel 85 therein aligned With the direction of travel of the components of the seam, the channel top and bottom walls embracing the edges of the pieces of material to be'joined, as shown in Figure 5. The entering end of channel 85, that is, the end at the bottom in Figure 4, and that outwardly of the paper in Figure 5, is flared so that the U shape tape leaving channel 8! enters channel 85 smoothly. Thereupon the tape is turned at right angles and is progressively presented in embracing relation to the other components of the seam, as shown in Figure 5. The channel 85 narrows somewhat toward its exit end so that the components of the seam are pressed closely together before passing into engagement With the presser foot and needles. The components of the seam, before binding tape 28 is assembled thereon, are guided by means of the top and bottom wires 80 and 82 on the left-hand end of body 14, between which the components pass. The longitudinally projecting finger 89 on the left-hand end of body 6 '14 engages the outer surface of the bight of the binding member and guides the assembled seam components accurately as regards lateral position.

Although for purposes of illustration I have shown and described a preferred embodiment of the seam of the invention and one particular mode of application of such seam as Well as a preferred embodiment of the method of forming such seam, it is to be understood that such embodiments are illustrative only and are not to be considered as limiting, since the invention is capable of considerable variation as to details. The invention is therefore defined by the scope of the following claims.

I claim as new the following:

1. A Welt seam joining and finishing the parallel and juxtaposed edges of pieces of flexible sheet material comprising a Welt member of U crosssection having a bight and flaps on both sides thereof, between the pieces of material adjacent such edges and parallel to such edges, thel Welt member consisting of a longitudinally folded tape, the bight of the Welt member being positioned inwardly of the edges of the pieces of material, the outer surfaces of the flaps of the Welt member lying parallel to and in contact with the inner surfaces of the pieces of material, the edges of the flaps of the welt member lying inwardly of the edges of the pieces of material but closer thereto than said bight, a binding strip of U cross-section having a bight and flaps on both sides thereof, said binding strip embracing the said edges of the pieces of material, the flaps of the binding strip overlapping a portion of the flaps of the welt member, a first line of stitching located parallel to the said edges of the pieces of material, the Welt member, and the binding strip and beyond the edges of the flaps of the binding strip, said first stitching extending through only one piece of material, the two flaps of the Welt member. and the other piece of material, in that order, and lying closely adjacent the bight of the Welt member, and a second line of stitching parallel to the first line of stitching and outwardly thereof, closer to the bight of the binding member, and beyond the edges of the flaps of the Welt member, said second line of stitching extending through only one flap of the binding member, one piece of sheet material, the other piece of sheet material, and the other flap of the binding member,

in that order.

2. In the Welt seam defined in claim 1, the welt member being cordless.

' ERWIN A. WIRT.

REFEREN CES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name b Date 1,314,408 Lewis Aug. 26, 1919 2,057,551 Bishop Oct. 13, 1936 

